This invention relates generally to a semiconductor processing system and, more specifically, to a semiconductor processing system having a processing chamber and a heat source assembly.
Rapid thermal processing (RTP) systems are employed in semiconductor chip fabrication to create, chemically alter or etch surface structures on semiconductor wafers. One such RTP system, as described in U.S. Pat. No. 5,155,336, includes a semiconductor processing chamber and a lamphead or heat source assembly located on the semiconductor processing chamber.
The semiconductor-processing chamber may be fitted with an adapter plate for low pressure operation. The adapter plate includes a lower quartz window, an upper quartz window and a strengthening component, which is sandwiched between the lower and upper windows. The strengthening component may be made of stainless steel and comprises two spaced plates and a surrounding ring, which jointly define an enclosed volume. A plurality of tubes are welded into holes in the plates to form light passageways.
A number of infrared lamps are located in the lamphead. During processing, infrared radiation from the lamps radiate through the upper window, the light passageways and the lower window onto a wafer in the processing chamber. In this manner, the wafer is heated to a required processing temperature.
During processing, the pressure within the processing chamber may be at a sub-atmospheric pressure, and the lamps may be operated cyclically. The cyclic operation can take place at different voltage profiles depending upon the process.
In general, the invention is directed to a semiconductor processing system. In one aspect, the invention features a process chamber having a window and a support on which a substrate may be positioned during processing. An assembly of radiant energy sources is located on a side of the window opposite from that of the support to direct radiant energy through the window and onto a substrate on the support. The radiant energy assembly can be filled with a thermally conductive gas to cool the radiant energy sources.
In another aspect, the invention is directed to an apparatus for processing a substrate. The apparatus includes a chamber having at least one wall and a window sealed to the at least one wall of the chamber. A heat source assembly including a plurality of radiant energy sources is provided to radiate regions of the substrate within the chamber with a pattern of radiation intensity. The heat source assembly is sealed to the window and means are provided for filling the heat source assembly with a thermally conductive gas, such as helium, to cool the radiant energy sources.
In yet another aspect, the invention features a system for rapid thermal processing of a substrate. The system includes a process chamber having a window, and an assembly of radiant energy sources and reflectors disposed outside of the process chamber adjacent to the window. The assembly directs radiant energy through the window onto a substrate in the process chamber. A gas source is provided to fill the assembly with a thermally conductive gas to cool the radiant energy sources.
The gas source may be a pressurized source of helium gas. A vacuum pump can be used to evacuate the radiant energy assembly. The reflectors can extend into a cooling chamber through which a coolant can be circulated. The interior spaces of the reflectors are in fluid communication with each other.
Among the advantages of the invention are that the onset of the sag-arc-out failure mode is delayed, and the life of the radiant energy sources is extended.
Other features and advantages of the invention will be apparent from the following detailed description, the accompanying drawings and the claims.